[luketapis]

Well I made an experiments and I have to answer a few question, there are 4 which I don't now how to make it. Any sugestions are very welcome

This is an experiment:

Part 1: Determination of bicarbonate in an Alka Seltzer tablet
Prepare the following 6 solutions of deionised water and ethanoic acid in a 100cm^3 beaker (one at a time)! Once the deionised water and acid have been placed into the beaker record the weight of the beaker. Then collect and weight an Alka Seltzer tablet and add it to the beaker.
Once the effervescence has stopped, reweight the beaker and its contents.
              Volume of H2O (cm^3)      Volume of ethanoic acid(cm^3)
Solution 1              35                                               0
s.2                     30                                               5
s.3                     25                                               10
s.4                     15                                               20
s.5                      5                                                30
s.6                      0                                                35
 
My results:
   Weight of baker and solution (g)   Weight of tablet (g)   Weight of baker, solution and tablet (g)   Weight difference   Mass of NaHCO3 reacted (g)   Percentage by mass NaHCO3 (%)
Solution 1   135.69   2.909    137.93   0.66            1.260   43.45
Solution 2   135.62   2.922    137.85   0.692     1.321   45.21
Solution 3   135.77   2.906    137.90   0.776            1.481   50.98
Solution 4   136.44   2.874    138.48   0.834            1.590   55.40
Solution 5   135.94   2.920    137.96   0.900            1.718   58.84
Solution 6   135.77   2.961    137.96   0.771            1.472   49.71

Part 2:
Determination of the Salicylate Content of Aspirin
Add 10.0 cm^3 of 2M sodium hydroxide to the beaker containing Solution 1 from Part 1. Then add a few anti bumping granules to this solution and boil gently for 10 min. Allow the solution to cool to room  temperature and transfer the solution into a 250 cm^3 volumetric flask and make up to the graduation mark using deionised water.
Then transfer 10.0 cm^3 of this solution into a 100 cm^3  volumetric flask and add 50.0 cm^3 Iron(III)nitrate solution and make up to the graduation mark using deionised water.
Record the absorbance of this solution using a UV spectrometer, then using this absorbance calculate the concentration of Salicylate present using Beer-Lambert law, A=ecl
My results for this part:
A=1.071
So:
1.071=4752n
n= 0.000225

Questions:

1.)Write the chemical equation corresponding to the reaction that causes the bubbling when an alka Seltzer is dropped into water.
Answer:
NaHCO₃ + H₂O→???

2.) How do the dissolution of CO₂(from the air) into the reaction solution and the evaporation of water affect affect  the results of the analysis, respectively?
??

3.) Interpret your graph of percentage by mass of reacted NaHCO₃ vs. Volume of acetic acid solution added in terms of the idea of limiting reagent.
?
4.) Calculate the mass of aspirin, acetylsalicylic acid (in grams), present in the tablet based on your results.
Answer:
n=0.000225 x 0.1=0.0000225
0.0000225 x 180 = 0.00405g

[Arkcon]

OK, can you begin to solve this for yourself?  For example, can you start with question 1?  Do you really have no idea what at least one product was?  Can you guess the rest, and then balance the equation?

[luketapis]

I now that one of the product was CO₂ but I don't know the whole equation.
Is it: Alka Selzer + water = .+ CO₂ ?

[Arkcon]

What does the experiment, as you wrote it above, say is in the beaker?

[luketapis]

solution 1, so just pure water and Alka Selzer

[Arkcon]

Nope.  Try again.  You're letting the monster block of text scare you from doing a good job on your own, which you'll need to do to pass the exam months from now.  For example:

Part 1: Determination of bicarbonate in an Alka Seltzer tablet
Prepare the following 6 solutions of deionised water and ethanoic acid in a 100cm^3 beaker (one at a time)!

I've added some emphasis for you.  Everything you need to do part 1 is included in the question.  You seem to have included, then excluded the in alternate responses.  Try to extract the information you need and pull it all together to answer question 1. Likewise, I think you'll find, once you get started, the rest of the questions are pretty straightforward.

[luketapis]

NaHCO₃+ CH₃COOH :rarrow:CH₃COONa + CO₂+ H₂O
Am I right?

[Arkcon]

Good.  You answered parts of this reaction at different times, so now you've pulled your work together.  So ... continue.